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Mary Leary — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Middlesex-County, Massachusetts
Our Model Tree links this Mary Leary across the 1930 and 1940 US Censuses in Middlesex-County, Massachusetts (XGBoost, ~Confirmed) — first a daughter (b.~1928), then head of a 6-person household.
Age 12
b. ~1928
Female
Daughter
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Middlesex-County, Massachusetts |
| Surname | Leary |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Arlington |
| 1935 Residence (County) | Middlesex |
| Additional Details | |
| Highest Grade | G 4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Arlington |
| Est. Birth Year | ~1928 |
Household Members
Census records only state relationship to the household head.
Pairwise kinship is derived (~90–95% accurate), not recorded.
Step/blended families and boarders can break it.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Helen Leary | Daughter | — | 22 | ~1918 |
| Lawrence Leary | Son | — | 16 | ~1924 |
| Dorothy Leary | Daughter | — | 14 | ~1926 |
| Mary Leary | Spouse | — | 40 | ~1900 |
| Arthur Leary | Head | — | 50 | ~1890 |
| Mary Leary | Daughter | — | 12 | ~1928 |
Census Appearances
1930
Norfolk, Massachusetts
Daughter, age 1
Norfolk, Massachusetts · implied b. ~1929 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leary |
| Given Name | Mary E. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 1 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Middlesex-County, Massachusetts
Daughter, age 12
Middlesex-County, Massachusetts · implied b. ~1928 — 6 household members
| Surname | Leary |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Arlington |
| 1935 Residence (County) | Middlesex |
| Highest Grade | G 4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
Model Tree
An inferred pedigree reconstructed from census links — up to 4 generations within the 1900–1950 window. Closer generations are built from household co-residence; deeper ones are bridged by following a relative to their own childhood census. Confidence compounds and weakens with each generation.
Our Model Tree links Mary Leary across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Leary
Daughter · 1940 · age 12 · b. ~1928 · Massachusetts
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Sibling
Dorothy Leary
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Helen Leary
Sibling · 1940 · age 22
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Lawrence Leary
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Middlesex-County, Massachusetts
Open full size
1940 US Federal Census — Middlesex-County, Massachusetts
Page Contents
19 people indexed on this census page (nara:1940:m-t0627-01602-00104)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Frank R Peterson | 52 | Head | Money Order Clerk | Massachusetts |
| 42 | Nona I Peterson | 52 | Wife | — | Massachusetts |
| 43 | Leslie F Peterson | 20 | Son | Bookkeeper | Massachusetts |
| 44 | Nona J Peterson | 25 | Daughter | Machine Operator | Massachusetts |
| 45 | Arthur Leary | 50 | Head | Meat Cutter | Massachusetts |
| 46 | Mary Leary | 40 | Wife | — | Massachusetts |
| 47 | Helen Leary | 22 | Daughter | — | Massachusetts |
| 48 | Lawrence Leary | 16 | Son | — | Massachusetts |
| 49 | Dorothy Leary | 14 | Daughter | — | Massachusetts |
| 50 | Mary Leary THIS PERSON | 12 | Daughter | — | Massachusetts |
| 51 | Rudolph Regat | 34 | Head | Superintendent | Latvia |
| 52 | Emma Regat | 32 | Wife | — | Latvia |
| 53 | Robert Regat | 5 | Son | — | Massachusetts |
| 54 | Audrey Regat | 3 | Daughter | — | Massachusetts |
| 55 | John Healey | 44 | Head | Operator | Massachusetts |
| 56 | Helen Healey | 42 | Wife | — | Massachusetts |
| 57 | Nora Healey | 20 | Daughter | Clerk | Massachusetts |
| 58 | Margaret Healey | 18 | Daughter | — | Massachusetts |
| 59 | Elizabeth Healey | 16 | Daughter | — | Massachusetts |
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1940 United States Federal Census (NARA). Our Model Tree links this person across census decades using XGBoost-based record linkage, with per-link confidence scores. Household corroboration strengthens the signal when co-residents appear on the same census pages in multiple years.
Source: National Archives and Records Administration (NARA)